Significant breakthrough in proprietary deepwater natural gas exploration in the northern South China Sea and its inspiration

• Main Author: Yuhong Xie
• Format: Article
• Language: English
• Published: KeAi Communications Co., Ltd. 2014-12-01
• Series: Natural Gas Industry B
• Subjects: Qiongdongnan basin; Deep water; Central canyon; Lingshui 17-2 gas reservoir; Neogene; Natural gas; Exploration; Significant breakthrough; Inspiration
• Online Access: http://www.sciencedirect.com/science/article/pii/S2352854014000321

In 2014, Zhanjiang Branch of CNOOC Limited obtained high oil and gas flows (160 × 104 m3/d) in Well LS 17-2-1 in northern South China Sea. The tested formation is the Neogene Upper Miocene Huangliu Fm. This is the first self-explored natural gas field in deep water area in China. Exploration in this area underwent three periods: (1) Reconnaissance exploration period (before 2002): Limited by techniques, the major exploration was in shallow water areas; (2) Foreign cooperative exploration period (2002–2012): As the discovered reserve scale was small, and there is no economic benefit, the partners successively gave up their exploration equities in the deep water area of western South China Sea; however, the high quality source rocks and reservoirs were confirmed in the deep water area of the South China Sea, revealing the mask of hydrocarbon exploration in this region; (3) Self-exploration period (since 2013): Relying on national science and technology major projects and its scientific research and production, Zhanjiang Company of CNOOC conducted several scientific researches on seismic data acquisition and processing, high-quality reservoir distribution, key factors for hydrocarbon accumulation in deep water areas, optimized and confirmed Lingshui 17-2 structure as the first drilling target, and obtained significant exploration breakthrough. Lingshui 17-2 structure is located in the Ledong-Lingshui section of the Central Canyon. Its major target layer is the Huangliu Fm. Its total thickness is over 150 m, with sandstone ratio of 75.4%, maximum single layer thickness of 52 m, porosity ranging 30.0%–33.7% (31.5% averagely), permeability ranging 293–2512 mD (633 mD averagely), belonging to reservoir with ultrahigh porosity and high-ultrahigh permeability. The exploration breakthrough in Lingshui 17-2 shows the giant potentiality of hydrocarbon exploration in this deep water area.